JP2010082691A - Forging method of hollow part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forging method of hollow parts capable of forming parts having through-holes from a long material in a simple forging process with scrap-zero manner, and smoothly discharging them from a punch. <P>SOLUTION: A long material A is fed so as to be projected from a die 3 by the predetermined length. The material A is gripped by a grip feed 11, and in this state, a punch 7 having a cylindrical punch body 70 having a forming recess 70a, an intermediate extrusion pipe 71, and a center pin 72 of the same dimension as the diameter of the material is advanced to the die side, and a front face of the punch body 70 is tightly attached to a front face of the die 3 to form a forming space R. Thereafter, the center pin 72 is advanced in the forming recess 70a and a projected portion of the material A is pushed back into the forming space R and formed in a desired shape. Further, the grip feed 11 is opened, the center pin 72 is advanced into the die 3 to separate the material A from a hollow parts B having a through-hole B1. When the punch 7 is retracted, the intermediate extrusion pipe 71 is advanced to the die side to discharge the hollow parts B from the punch 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for forging a hollow part in which a hollow part having a volume of at least twice the wire diameter and having a through hole in the center is repeatedly formed at zero scrap from a long linear material.

  Conventionally, as a method of forging a hollow part having a through-hole in the center, first, a long material is cut into a predetermined length, and then the cut material is transferred to a first-stage forging process, The die and punch are used to form a solid intermediate product with the desired outer shape, then the intermediate product is transferred to the first forging process, and the center of the intermediate product is punched out using the die and punching punch. Through holes are formed to form hollow parts that are final molded products.

  However, according to the above conventional forging method of hollow parts, a cutting process (cutting mechanism) for cutting a long material into a predetermined dimension is required separately from the forging process, and cutting is performed by the cutting mechanism. Since the blank having a predetermined dimension has the same cross-sectional shape as that of the material, many forging steps from the shape of the blank to the final molded product are required. As a result, the forging machine becomes complicated, becomes large and expensive, and has a problem that material loss occurs because the center portion of the intermediate molded product is punched to form a through hole.

  Therefore, the present invention has been devised in view of the above problems, and it is possible to repeatedly forge a hollow part having a volume more than twice the diameter of a material from a long material without scraping, and smoothly eject it from the punch. An object is to provide a method for forging hollow parts that can be produced.

In order to solve the above-mentioned problems, the present invention provides a method for forging a hollow part in which a hollow part having a volume more than twice the diameter of a raw material and having a through hole in the center is repeatedly formed at zero scrap. First, the material is supplied by the supply mechanism so that the tip portion protrudes from the through hole of the die to the front side by a predetermined length, and then the material is gripped by an openable / closable grip feed provided on the die side, On the die side, a punch with a cylindrical punch body that forms the molding recess, an intermediate extrusion pipe that can be advanced and retracted into the molding recess, and a center pin that has the same size as the material diameter, while maintaining the protruding state. The front surface of the punch body is brought into close contact with the die front surface to form a desired molding space by the die, the punch body and the intermediate extrusion pipe, and then the center pin is advanced to the middle in the molding recess. Push the projecting part of the material back into the molding space to form it into the desired shape, and then open the grip feed to release the material grip and then advance the center pin further into the die through-hole. A hollow part having a through-hole is formed without scraping by separating into a molded product having a hole and a linear material, and then the punch is retracted from the die and the intermediate extrusion pipe is advanced to the inside of the molding recess. The hollow parts are discharged from the punch to the outside.
In addition, a hollow part is the concept containing the intermediate molded product which has a through-hole before performing final shaping | molding in a post process.

  According to the present invention, a hollow part having a volume of at least twice the wire diameter from a long material and having a through-hole in the center portion (an intermediate having a through-hole before performing final molding in a subsequent process) according to the present invention. (Including molded products) can be repeatedly formed at zero scrap by a simple one forging process. Moreover, the punch has a cylindrical punch body that forms the molding recess, an intermediate extrusion pipe that can be advanced and retracted into the molding recess, and a center pin that has the same dimensions as the material diameter. When the punch is retracted from the die, the intermediate extrusion pipe can be advanced to the inside of the molding recess to forcibly eject the hollow part remaining in the molding recess from the punch to the outside. As a result, for example, the intermediate molded product discharged from the punch by the intermediate extrusion pipe can be securely clamped by the transfer chuck, and the transfer chuck can perform not only parallel transfer but also turn transfer such as 90 ° or 180 °. It can be accurately transferred to the process. By such a turn transfer, it becomes possible to form the desired shape and dimension while eliminating burrs and deformations generated during punching in the next step.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view of a hot forging machine used in the method for forging a hollow part according to the present invention. Here, the forging machine 1 has three stages of forging processes S1, S2, and S3. First, in the first stage of forging process S1, the volume from the long material A is more than twice the wire diameter, and the through hole B1. The intermediate molded product B as a hollow part having forging is forged without scrap, and then the outer ring C and the inner ring D of the bearing are integrally formed from the intermediate molded product B in the second stage forging step S2, and then the third stage. In the eye forging step S3, the outer ring C and the inner ring D are separated without scrap.

  Specifically, the forging machine 1 includes a plurality of dies 3 to 5 fixed at predetermined positions on the machine base 2, and a die 3 on the front side of the ram 6 that advances and retreats toward the dies 3 to 5. As many as 5 punches 7 to 9 are arranged to face each other, and these die 3 to 5 and punches 7 to 9 constitute three stages of forging steps S1, S2, and S3.

  In the first forging step S1, as shown in FIG. 2, the die 3 is fixed at a predetermined position of the machine base 2, and the die 3 is moved forward on the front side of the die 3 so as to face the die 3. A retracting punch 7 is provided. Further, on the rear side of the die 3 of the machine base 2, an openable and closable grip feed 11 for holding and holding a long material A having a circular cross section heated to a high temperature by an appropriate heater (not shown) is provided. In addition, a supply mechanism (not shown) such as a feed roller for supplying the material A to the die 3 side by a predetermined length L is provided.

  The die 3 has a through hole 3a through which the material A can be inserted. The punch 7 is provided so as to be able to advance and retreat in a cylindrical punch body 70 having a molding recess 70a on the front surface and a through hole 70b formed in the center of the molding recess 70a, and a part of the molding recess 70a is provided. An intermediate extruding pipe 71 is provided, and a center pin 72 is provided in the inner hole 71a of the extruding pipe 71 so as to be able to advance and retract. The center pin 72 has the same dimensions as the material A diameter, and is appropriately retracted at a predetermined timing in accordance with the movement position of the punch 7 by a driving mechanism (not shown), as shown in FIG. The molding advance position in the molding recess 70a shown in FIG. 5 and the cutting advance position in the through hole 3a shown in FIG. 5 are moved forward and backward. Further, when the punch 7 is retracted from the die 3 after forming the intermediate molded product B by an appropriate extrusion mechanism (not shown), the intermediate extruded pipe 71 is advanced into the molding recess 70a. The intermediate molded product B to be left in the molding recess 70a is forcibly discharged from the punch 7 to the outside.

  The grip feed 11 includes a plurality of grip bodies 11a and 11b that can be opened and closed so as to sandwich the material A, and an opening and closing mechanism (not shown) using air or hydraulic pressure that opens and closes the grip bodies 11a and 11b.

  On the other hand, in the second forging step S2, a die 4 having a stepped molding portion 4a is provided on the machine base 2, and a knockout pin 12 that can be advanced and retracted toward the punch 8 is provided at the rear side of the center of the die 6. Is provided. The ram 6 is provided with two stepped molding punches 8 for integrally molding a large-diameter outer ring C and a small-diameter inner ring D of the bearing. Here, the inner diameter of the outer ring C and the outer diameter of the inner ring D are formed to be the same, and the outer ring C and the inner ring D are connected via a narrow part in a state of being displaced in the central axis direction.

  Further, in the third forging step S3, the die 5 having the stepped cutting part 5a is provided in the machine base 2, and the inner ring D separated on the rear side of the center part of the die 5 is discharged to the outside. A passage 13 is formed. Further, the ram 6 is provided with a separation punch 9 for separating the integrally formed outer ring C and inner ring D without scraping, and an outer ring C which is to remain on the outer periphery of the separation punch 9 on the punch side of the machine base 2. A stripper 14 is provided for forcibly discharging the punch 9 to the outside.

  Next, a method for forging parts will be described based on the forging machine described above.

  First, in the first forging step S1, the long material A heated to about 1100 ° C. with the grip feed 11 opened is advanced by the supply mechanism, and the material A as shown in FIG. Is fed so as to project a predetermined length L from the inside of the through hole 3a of the die 3 to the front side thereof.

  Next, the grip feed 11 is closed and the material A is gripped at the protruding position by the grip feed 11.

  Thereafter, the punch 7 is advanced to the die 3 side while keeping the protruding state, and the front surface of the punch body 70 is brought into close contact with the front surface of the die 3. Thereby, as shown in FIG. 3, an annular molding space R is formed by the front surface portion of the die 3, the molding recess 70 a of the punch body 70, and the front surface of the intermediate extrusion pipe 71.

  Thereafter, the center pin 72 in the intermediate extrusion pipe 71 is advanced to the middle in the molding recess 70a as shown in FIG. 4, and the protruding portion of the material A is pushed back into the molding space R to be integrated with the material A. A circular head A1 is formed.

  Thereafter, the gup feed 11 is opened to release the gripping of the material A, and then the center pin 72 is further advanced into the through hole 3 a of the die 3. Thereby, as shown in FIG. 5, the raw material A and the head A1 integrated therewith are cut off, and the intermediate molded product B having the through hole B1 is forged without scrap.

  Thereafter, the punch 7 is retracted from the die 3 and the intermediate extrusion pipe 71 is advanced to the inside of the molding recess 70a to forcibly discharge the intermediate molded product B to be left in the molding recess 70a from the punch 7 to the outside. To do.

  Then, the intermediate molded product B discharged from the punch 7 by the intermediate extrusion pipe 71 is sandwiched by a transfer chuck (not shown), and is transferred to the second forging step S2 by performing 180 ° turn transfer by this transfer chuck. To do. In the second forging step S2, as shown in FIG. 1, the intermediate molded product B is forged with a die 4 having a stepped molding recess 4a and two stepped molding punches 8 to provide a large-diameter outer ring of the bearing. C and the small-diameter inner ring D are integrally formed. At this time, since the 180 ° turn transfer is performed in the transfer chuck transfer, the shape and dimensions are obtained while eliminating the burr and deformation generated during the punching in the first forging step S1 in the second forging step S2. It becomes possible to mold.

  Thereafter, the punch 8 is moved backward from the die 4 and the knockout pin 12 is moved forward to the die side, so that the integral outer ring C and inner ring D are discharged from the die 4 to the outside.

  Then, the integral outer ring C and inner ring D discharged from the die 4 by the knockout pin 12 are sandwiched by a transfer chuck (not shown) and transferred in parallel to the third forging step S3 by the chuck. In the third forging step S3, as shown in FIG. 5, the outer ring C and the inner ring D are cut into the outer ring C and the inner ring D by advancing the separation punch 9 toward the die 5 side having the stepped cutting portion 5a. To separate. Thereby, the annular outer ring C and the annular inner ring D in the bearing shown in FIG. 6 are manufactured efficiently and consistently without scrap. The inner ring D is fed into the discharge passage 13 provided on the rear side of the center portion of the die 4 by the separation punch 9 and discharged from the discharge passage 13 to the outside. On the other hand, the outer ring C remains on the outer periphery of the separation punch 9, but when the separation punch 9 is retracted, the outer ring C is forcibly removed from the punch 5 by the stripper 14 provided on the punch side of the machine base 2 and exposed to the outside. Discharged.

  As described above, according to the method of forging a part part of the present invention, a simple forging of an intermediate molded product B having a volume of more than twice the diameter of a wire from a long material A and having a through-hole B1 at the center. Can be formed with zero scrap in the process. In addition, the punch 7 has a cylindrical punch body 70 having a molding recess 70a, an intermediate extrusion pipe 71 that can be advanced and retracted into the molding recess 70a, and a center pin 72 having the same size as the material diameter. After forming the intermediate molded product B, when the punch 7 is retracted from the die 3, the intermediate extruded pipe 71 is advanced to the inside of the molding recess 70a, and the intermediate molded product B which is to remain in the molding recess 70a is punched 7 Can be forcibly discharged to the outside. As a result, the intermediate molded product B discharged from the punch 7 can be securely held by the transfer chuck, and can be accurately transferred to the second forging process by performing a 180 ° turn transfer by the transfer chuck. . By this turn transfer, the burrs and deformation generated at the time of punching can be formed into the required shape and dimensions in the next process. Moreover, the intermediate molded product B is used by further connecting the second and third forging steps S2 and S3 to the first forging step S1 forging the intermediate molded product B having the through-hole B1. Furthermore, the outer ring C and the inner ring D of the bearing can be manufactured consistently and efficiently without scrap.

  In addition, the raw material A may be a bar material, or may be an extension of a coil wire. In addition, the material A may be forged after being heated to a warm or hot state by its steel type or the like, but if it is heated to a high temperature as in the above-described embodiment, an intermediate molded product having a complicated shape or This is good because hollow parts can be easily and precisely forged.

  Further, in the above-described embodiment, the intermediate molded product B having a volume of at least twice the wire diameter and having the through-hole B1 is forged without scrap in the previous process, and then intermediate in the subsequent process. Although the case where the outer ring C and the inner ring D of the bearing are simultaneously forged from the molded product B without scrap is described, of course, the intermediate molded product B may be used as a final hollow part (final forged product) as it is.

  It is a schematic explanatory drawing of the forging machine used with the forging forming method of the hollow part which concerns on this invention.   It is explanatory drawing of the forge 1st operation | movement in the forge process of the 1st step | paragraph.   It is forge 2nd operation | movement explanatory drawing in the forge process of the 1st step | paragraph.   It is forge 3rd operation | movement explanatory drawing in the forge process of the 1st step | paragraph.   It is explanatory drawing at the time of completion | finish of the forge operation | movement in the forge process of the 1st step | paragraph.   It is explanatory drawing of the outer ring | wheel and inner ring | wheel of a bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Forging machine 2 Machine stand 3 Die 3a Molding recess 7 Punch 70 Punch main body 70a Molding recessed part 71 Intermediate extrusion pipe 72 Center pin 11 Grip feed A Material B Intermediate molded product (hollow part)
B1 Through hole

Claims (1)

  A hollow part forging method in which a hollow part having a volume of more than twice the diameter of a material and having a through-hole in the center is repeatedly formed with zero scrap. The part is fed so that it protrudes to the front side from the through hole of the die by a predetermined length, and then the material is gripped by an openable / closable grip feed provided on the die side and the protruding state is maintained. A punch with a cylindrical punch body that constitutes the center, an intermediate extrusion pipe that can be advanced and retracted into the molding recess, and a center pin with the same dimensions as the material diameter is advanced to the die side, and the front surface of the punch body is in close contact with the die front surface. The die, punch body, and intermediate extrusion pipe form a desired molding space, and then the center pin is advanced to the middle of the molding recess to push the projection of the material back into the molding space. After that, after opening the grip feed and releasing the grip of the material, the center pin is further advanced into the through hole of the die to separate the molded product having the through hole from the linear material. A hollow part with a through hole was formed without scrap, and then the punch was retracted from the die and the intermediate extrusion pipe was advanced to the inside of the molding recess so that the hollow part was discharged from the punch to the outside. A forging method for hollow parts characterized by the above.

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